[MIPS] Make SPARSEMEM selectable on QEMU.

This might be helpfull to debug sparsemem on mips.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -480,6 +480,7 @@ config MOMENCO_OCELOT_G
 	select SYS_SUPPORTS_32BIT_KERNEL
 	select SYS_SUPPORTS_64BIT_KERNEL
 	select SYS_SUPPORTS_BIG_ENDIAN
+	select ARCH_SPARSEMEM_ENABLE
 	help
 	  The Ocelot is a MIPS-based Single Board Computer (SBC) made by
 	  Momentum Computer <http://www.momenco.com/>.
@@ -1692,6 +1693,9 @@ config ARCH_DISCONTIGMEM_ENABLE
 config ARCH_SPARSEMEM_ENABLE
 	bool
 
+config ARCH_SPARSEMEM_ENABLE
+	bool
+
 config NUMA
 	bool "NUMA Support"
 	depends on SYS_SUPPORTS_NUMA